Hydraulic jar



Dec. 9, 1941. R. L. KERR 2,265,431

HYDRAULIC JAR Filed Jan. 11, 1939 561/. f; 4 1 76.2. [00, /g 7 l4 /6/ v 4 //VVE/V70/? W/TA/FSS: W .fi aa 1, Kerr m I UMEY v w ly/ ra/wv zyg.

Patented Dec. 9, 1941 Ralph L. Kerr, Oklahoma City, Okla; assignor of I one-half to" J. Eldon Peek, Oklahoma City,

Okla.

Application January 11, iasasenal No. 250,276 4 Claims. 01. 255-27) This invention relates to a jar for use in well drilling operations designed to impart severe jarring action to a lost tool or the like which it is desired to dislodge from a bore hole.

It frequently happens that tools or other devices are lost in a bore hole and after they are engaged by the usual fishing tools that they can- 'not be dislodged from the formation by the usual pulling methods. The caved-in materials surrounding the lost tool are frequently compacted to such extent that circulation of mud cannot be efiected to wash them away and release the tool. Accordingly. the dislodging of the tool can only be effected by .the use of a so-called jar, which by applying a severe jarring action, generates vibrations in the tool tending to free it. The ordinary type of jarring tool consists of an outside case slidably fitted over an anvil. The outer case is initially located by means of engaging devices between it and the anvil in a relaitvely low position with respectto the-anvil so that a pull may be exerted on a drill pipe to which the case is secured until a severe strain is eiiected, whereupon the strain is suddenly released by turning the case, with the result that the drill pipe snaps upwardly causing the case to strike a shoulder on the anvil and exert a hammering action thereon.

Devices of this type have taken various forms,

but .in general it is required that there be pro-. vided between the jar and the surface a string of pipe in order that a twisting action may be secured to effect the release. Additionally, a

fault common to all of the jars heretofore pro- -3 one, whereas the piston 6 has quite considerable vided has been that during the short interval be tweenrelease and the blow the strain on the fishing tool is released and consequently the fishing tool and the lost tool which it engages may drop downwardly to-such extent that the blow isnot transmitted to the formations, the energy being dissipated solely in arresting the downward movement of the fishing tool and 10st tool which it engages.

The broad objects of the present invention are first to provide a jar which does not require the use of a string of pipe for its operation, since only a pull need be transferred from the surface without any torsional stress. and secondly the proviis secured to dislodge the lost tool from the .formation.

Other objects of the invention, particularly relating to. details of construction, will become ap- 5 'parent'from the following description, read in conjunction with the accompanying drawing, in which:

drill string; and

Figure 2' is a similar section, but showing a modification for operationby means of a wire line. P

1 Referring first to the'modification of Figure 1,

the improved jar comprises a casing 2 which may contain, or which may be connected to, conventional fishing tool elements. Since the fishing portion of they apparatus may take any of the 0 usual conventional forms it need not be described in detail. It is sufficient to say that it is of the form adapted to engage a lost tool or the like which is to be dislodged from a caved-in formation in a hole.

The housing 2 is provided with a bore indicated at 4 within which slides a piston 8 closely fitting its walls and preferably provided with piston rings or other packing means to confine beneath it air under high compression. The piston 8 is -'3 'carried by a rod Hi to the lower end of which is secured a piston member I! arranged to move within a more restricted extension 6 of the cylinder l. The fltof the piston I! in the extension 6 of the cylinder is arranged to be a quite close clearance with the upperenlarged portions of the cylinder. The-junction of the two portions of the cylinder is indicated at 14 in the form of a shoulder which may be engaged by the tapered 40 lower portions of the piston member l2 to center thesame inthe cylinder extension 6.

The piston member I! is provided with a, plurality of vertical ports I 6, adapted to be closed by a ring l8 acting as a check valve preventing the passage of liquid 2i! downwardly through the port It, but permitting its free upward passage.

Communicating withthe space under the pis- ,ton B there may be a suitable check valve arrangement indicated at, through which air or 0 other gas may be introduced at exeremely high pressure and maintained within the cylinder.

" -Above the piston 8 there is located a second piston 24 which however, need not have any gas-tight fit within the cylinder 4. The piston 5 24 is carried by area 26, which passes through him I {I V cock the apparatus, this. vaction maybe piston'll' into enga a 3 the upper-end of the cylinder. 'Ifl'iereafter, asin 1;- the caseofthe previous modification; the piston 8 will move upwardly slowly until theypist'on i25 "clearsthe lower restricted portion 6' ofgthecylshould be of the order of pressures encountered in the bore hole at the depth at which the apparatus is used. Under such circumstances it will be evident that the piston 8 will move to its uppermost position carrying with it the rod 26.

The instrument-is now lowered within the bore hole by building up a drill stem attached to the rod 26. When the fishing tool engages the lost tool which is to be removed from the hole, the

on the apparatus, whereupon the piston 24 will be forced downwardly forcing the piston 8 downwardly, and vwithit the piston l2, which will pass freely into the reduced section of the bore because of theopening of the check valve l8. Such action cocks the apparatus, and it will remain in such 1 condition until it is desired to effect the impact serving to loosen the lost tool.

I When it is desired to cause the impactto take place, the drill stem is raised pulling the piston 24 i to the top of the cylinder 26. The piston 8 will not follow it immediately because of the limited clearance between the piston l2 and its bore 6, and that piston will move upwardly only at a slow rate, depending upon the leakage of the oil or other liquid past it to the bottom of the cylinder 6.

The clearance between this, piston and such cylinder may be made to provide any desired rate of rise of the piston. As soon as the piston clears the shoulder H, however, it may rise with great 10 piston 6 under very high pressure. This pressure weight of the drill stem may be permitted to rest pistons 6 and 8', it be obvious that a strong spring may be used which would force the piston 8 upwardly, though it would yield in the cocking of the apparatus under the weight of the drill- Y i 5 stem in the case of Figure l, or under the superior force of an upper spring in the case of the modification of Figure 2. What I claim Patent is; 1

- 1. A jarring device for use in bore holes comprising a member adapted for engagement within the hole and providing a cylinder, a supporting member movable relatively to the first member and having a portion movable in said cylinder, a hammer element comprising a piston located in said cylinder movable relatively to said supporting member; said cylinder having a small bore portiona closely fitting said pistonand acommunicating enlarged bore portion loosely fitting said piston, means for urging said piston from the small bore portion of the cylinder into the large bore portion thereof, and liquid within said cylinder, said portion of the supporting member movable in the cylinder engaging said hammer element to force device, and the slow leakage of liquid past said piston in the small bore portion of the cylinder delaying for a substantial period the occurrence of a blow by said hammer until said supporting member disengages said hammer element and may engage and exert a direct upward stress on said first mentioned member.

2 A jarring device for use in bore holes comprising a member adapted for engagement within the hole, a supporting member movable relatively to the first member, a hammer element, means eflective upon downward movement of said supporting member relative to the first member to cock said hammer element, said supporting mem- 40 her being movable upwardly relatively to the first rapidity under the action oi the highly com-} pressed gas below the piston 8, and consequently i1 the piston 8 and its assembly will act as a hammer to be violently drivenagainst the piston 24. Dur- 5 ing all of this time,. or course,; an upward stress anynecessary number of times.

, In Figure 2 theregis disclosed an apparatus almost identical with Figure l, and'in which cor-- responding parts are designated by the same refof a wire line.

their lowermost positions. In causing the jarring ratus maybe again cocked merely byreleas'ing piston downwardly. .7

' erence characters primed. This apparatus, how

ever, is of a form adapted to be operated by means 1 1 Since in such case there will be insufiicient weight to cock theapparatus, there is] Y provided a very strong spring 32, which will be strong enough'to force the pistons 24' and 8' to action to take. place, an upward force is exerted .j

on they wire line, preferably bringing-"the upper gement with the shoulder-ata the wireline topermit the spring 32 te-force the can be exerted on thefishing' 'tool, which will} l insure hat the. impact has the greatest possible} I 1. effect in'ja'rring'free rromth'e" formation the lost" tooli,irBy'liierelylowering the drill stem so "as to 0 o e e the summing memberand 1 a repeated "of said direct upward stress of the supporting Y L member. on the first member, to efiect automati'- cally. and during the continued exertion of.said

directiupward stress, the delivery of .aJarring blow by said hammer element'under the action of member and independently of said hammer element after said cocking action to a position to engage and exert a direct upward stress on the first member, means for urging said hammerelesaid urging means;

3; A jarring device for in bore holes com- V V prising a member adapted for engagementwithin the hole, a supporting member movable relatively to the first member, a hammer element, means effective upon downward movement of. said suporting'member relative to the first member to cock said hammer element, said supporting mem- 'lberbeing'movable upwardly relatively to the first, on.

member and independently'of said hammer element;after" said cocking action to a position to en'gagemnd exert a direct. upward stress on the :'first'member, means for urging said hammer ele- "I ment out of cooked position, and means'operabl e inder, whereupon a rapid upward movement will 1 occurto produce the jarring action. The appa firstto restrict by restricted hydraulic flow action movements of the hammer.- element after said upward movement of the supporting member and following .s'uchu'pward movement of the supportand desire to protect by Letters the piston into the small bore portion to cock the ment out of cooked position, and means operable their, J after substantial predetermined time delay memberlanda-exertion ofsaid direct upward stress of the supporting member on the first member, to efiect automatically, and during the continued exertion of said direct upward stress, the delivery of a jarring blow by said hammer element under the action of said urging means.

4. A jarring device for use in bore holes comprising a member adapted for engagement within the hole, a supporting member movable relatively to the first member, a hammer element, means effective upon downward movement of said supporting member relative to the first member to cock said hammer element, said supporting member being movable upwardlyrelatively to the first member and independentlyot said hammer elementafter said cocking action to a position to 15 engage and exert a direct upward stress on the first member, elastic means for urging said hammer element out of cocked position, and means operable first to restrict movements of the hammer element after said upward movementof the supporting member and then, after substantial predetermined time delay following such upward movement of the supporting member and exertion of said direct upward stress of the supporting 10 member on the first member, to effect automatically,.and during the continued exertion of said direct upward stress, the delivery of a jarring blow by said hammer element under the action of said urging means.

RALPH L. KERR. 

